Walker On The Wild Side; Already famous in Europe, Swiss architects Herzog & de Meuron are about to leave their first mark on the United States. But they're not stopping there.(Walker Art Center in Minneapolis)

Byline: Cathleen McGuigan

As everyone knows, winter is still blasting the American Midwest. Besides the blustery snow, a giant ice cube has landed in Minneapolis--and it's not going to melt by spring. "A big ice cube for Ice City," jokes the avant-garde European architect Jacques Herzog, one half of the Basel-based team of Herzog & de Meuron, who've designed the expansion of the city's Walker Art Center, opening next month. The tour de force of their building is the silvery five-story cube, with its daredevil cantilevered corner hovering over the entrance--anchored by hidden tons of steel and concrete--and the whole shebang wrapped in shimmering aluminum-mesh panels that look as light and luscious as crumpled silk.

What makes this a big deal is not just that the building is so cool but that we've been waiting so long for these Swiss masters to build something major in the United States. When they went to America in 2001 to collect architecture's biggest honor, the Pritzker Prize, they were barely known there. The award was presented at Thomas Jefferson's Monticello--an incongruous setting given what their architecture looks like--and on the day of the ceremony you could spot the pair a mile away on the quaint streets of historic Charlottesville, Virginia: they were the uber -hip Euro-guys dressed in black. Their breakthrough project, the Tate Modern in London, had just opened the year before, and Herzog and Pierre de Meuron were young for Pritzker laureates (they were each 50--kids in a profession of late bloomers). Since then, they've leveraged their European successes to go global, with such high-profile projects as the jewel-like $80 million Prada store in Tokyo and the commission for the 2008 Olympic Stadium in Beijing, a design that looks like a gigantic bird's nest. Herzog & de Meuron don't have a signature style: every building looks different. With each project, says Herzog simply, "we want to do something that has not been done in architecture."

They snagged the commission to design the Walker in 2000, after they had been hired to design the new de Young Museum in San Francisco. (That dazzling--and, of course, quite different--building will open next October.) Given that the Walker, founded in 1879, is probably the leading American venue for cutting-edge artists (both visual and performing), it may seem obvious that such avant-garde darlings as Herzog & de Meuron would be asked to add to the stark modern box designed by Edward Larrabee Barnes in 1971. Two wild and crazy guys for a wild and crazy place, right? Well, let's not hyperventilate. Their work has rigor--they are Swiss, after all--and the new Walker is practical as well as daring. Yet it clearly showcases the architects' gifts for deploying unusual materials in unexpected ways and for achieving a remarkable sense of lightness.

Herzog and de Meuron met in kindergarten and first collaborated with LEGOs (we're not making this up). Neither dreamed of becoming an architect, but after false starts in other fields--Herzog in biology and philosophy, de Meuron in structural engineering--they decided to join forces and study architecture. They founded their firm in 1978. Even their small early projects were evocative and original, toying with architecture's most basic forms: they once designed a concrete house reminiscent of a Monopoly token, with a steeply pitched roof and no eaves, and a chimney poking up as if a child had drawn it. A stunning signal tower for the Basel train station was a twisted box wrapped in copper strips, and the whole object seemed to glow.

The Walker addition is full of similar surprises, starting with the ice cube and its weird-shaped windows (deputy director Richard Flood has dubbed the shapes "schnitzels"). There are even bigger surprises waiting ...